Question 1

The population of a city was 8,00,000 in 2020. It increased by 15% in 2021 and decreased by 10% in 2022. In 2023, it again increased by 20%. What is the population of the city at the end of 2023?

Accepted Answer

Step 1: Population after 2021 = 8,00,000 × 1.15 = 9,20,000. Step 2: Population after 2022 = 9,20,000 × 0.90 = 8,28,000. Step 3: Population after 2023 = 8,28,000 × 1.20 = 9,93,600. Therefore, the answer is 9,93,600.

Question 2

The population of a city was 500,000 in 2020. If it increased by 20% in 2021, what was the population at the end of 2021?

Accepted Answer

Step 1: Initial population = 500,000. Step 2: Increase = 20% of 500,000 = 0.20 × 500,000 = 100,000. Step 3: Final population = 500,000 + 100,000 = 600,000.

Question 3

A town's population decreased by 15% over one year. If the population at the end of the year was 170,000, what was the population at the beginning of the year?

Accepted Answer

Step 1: Let initial population = P. Step 2: After 15% decrease, population = P × (1 - 0.15) = 0.85P. Step 3: 0.85P = 170,000. Step 4: P = 170,000 ÷ 0.85 = 200,000.

Question 4

In 2019, a village had 80,000 people. In 2020, the population increased by 25%. In 2021, it increased by 10%. What was the population in 2021?

Accepted Answer

Step 1: Population in 2020 = 80,000 × 1.25 = 100,000. Step 2: Population in 2021 = 100,000 × 1.10 = 110,000.

Question 5

If a region's population increases from 400,000 to 480,000, what is the percentage increase?

Accepted Answer

Step 1: Increase = 480,000 - 400,000 = 80,000. Step 2: Percentage increase = (80,000 ÷ 400,000) × 100 = 0.20 × 100 = 20%.

Question 6

The population of village A is 80,000 and the population of village B is 120,000. By what percentage is village B's population more than village A's population?

Accepted Answer

Step 1: Difference = 120,000 - 80,000 = 40,000. Step 2: Percentage more = (Difference ÷ Village A's population) × 100. Step 3: Percentage = (40,000 ÷ 80,000) × 100 = 0.5 × 100 = 50%.

Question 7

A city's population was 250,000 in 2018. By 2020, it had grown to 360,000. What was the percentage increase in population over these two years?

Accepted Answer

Step 1: Increase in population = 360,000 - 250,000 = 110,000. Step 2: Percentage increase = (Increase ÷ Original) × 100 = (110,000 ÷ 250,000) × 100 = 0.44 × 100 = 44%.

Question 8

A district's population was 600,000. After a 30% increase, what is the new population?

Accepted Answer

Step 1: Original population = 600,000. Step 2: 30% of 600,000 = 0.30 × 600,000 = 180,000. Step 3: New population = 600,000 + 180,000 = 780,000.

Question 9

In a city, the population increased from 4,00,000 to 4,84,000 over two years. If the increase in the first year was 10%, what was the percentage increase in the second year?

Accepted Answer

Step 1: Population after first year = 4,00,000 × 1.10 = 4,40,000. Step 2: Population after second year = 4,84,000. Step 3: Increase in second year = 4,84,000 − 4,40,000 = 44,000. Step 4: Percentage increase in second year = (44,000 ÷ 4,40,000) × 100 = 10%. Therefore, the percentage increase in the second year was 10%.

Question 10

A town's population increases by 25% every year. If the population was 1,28,000 at the end of 2021, what was the population at the end of 2019?

Accepted Answer

Step 1: Population at end of 2021 = Population at end of 2019 × (1.25)². Step 2: 1,28,000 = P × 1.5625. Step 3: P = 1,28,000 ÷ 1.5625 = 81,920. Therefore, the population at the end of 2019 was 81,920.

Question 11

The population of a city increases by 20% in the first year and then decreases by 10% in the second year. If the population after 2 years is 216,000, what was the initial population?

Accepted Answer

Step 1: Let initial population = P. After 1st year: P × 1.20. After 2nd year: P × 1.20 × 0.90 = P × 1.08. Step 2: P × 1.08 = 216,000. Step 3: P = 216,000 ÷ 1.08 = 200,000.

Question 12

A town's population was 500,000 in 2015. It increased by 15% by 2018 and then decreased by 20% by 2021. What is the population in 2021?

Accepted Answer

Step 1: Population in 2018 = 500,000 × 1.15 = 575,000. Step 2: Population in 2021 = 575,000 × 0.80 = 460,000.

Question 13

In a city, the male population is 55% of the total. If the female population is 180,000, what is the total population of the city?

Accepted Answer

Step 1: If males are 55%, then females are 45% of total. Step 2: 45% of Total = 180,000. Step 3: Total = 180,000 ÷ 0.45 = 400,000.

Question 14

A city's population was 250,000 in 2010. By 2015, it became 300,000. By 2020, it became 360,000. What is the percentage increase from 2015 to 2020 compared to the increase from 2010 to 2015?

Accepted Answer

Step 1: Increase from 2010 to 2015 = 300,000 - 250,000 = 50,000. Step 2: Increase from 2015 to 2020 = 360,000 - 300,000 = 60,000. Step 3: Percentage increase in growth = (60,000 - 50,000) ÷ 50,000 × 100 = 10,000 ÷ 50,000 × 100 = 20%.

Question 15

The population of a city was 5,00,000 in 2020. It increased by 20% in 2021 and then decreased by 10% in 2022. What is the population at the end of 2022?

Accepted Answer

Step 1: Population after 20% increase in 2021 = 5,00,000 × (1 + 20/100) = 5,00,000 × 1.20 = 6,00,000. Step 2: Population after 10% decrease in 2022 = 6,00,000 × (1 - 10/100) = 6,00,000 × 0.90 = 5,40,000. Therefore, the population at the end of 2022 is 5,40,000.

Question 16

The male population of a village is 60% of the total population. If the female population is 8,000, what is the total population of the village?

Accepted Answer

Step 1: If male population is 60%, then female population is 40% of total. Step 2: Let total population = T. Then 40% of T = 8,000. Step 3: 0.40 × T = 8,000. Step 4: T = 8,000 ÷ 0.40 = 20,000. Therefore, the total population is 20,000.

Question 17

In a city, 35% of the population are children and 60% are adults. The remaining population consists of senior citizens. If there are 1,50,000 senior citizens, what is the total population of the city?

Accepted Answer

Step 1: Percentage of senior citizens = 100% - 35% - 60% = 5%. Step 2: Let total population = P. Senior citizens = 5% of P = 0.05P. Step 3: 0.05P = 1,50,000, therefore P = 1,50,000 ÷ 0.05 = 30,00,000. The total population is 30,00,000.

Question 18

A state's population increased from 80 lakhs to 1 crore in 5 years. What is the average annual percentage increase in population?

Accepted Answer

Step 1: Initial population = 80 lakhs = 80,00,000. Final population = 1 crore = 1,00,00,000. Step 2: Using compound growth formula: P(1 + r/100)^n = Final. 80,00,000(1 + r/100)^5 = 1,00,00,000. Step 3: (1 + r/100)^5 = 1.25. Step 4: 1 + r/100 = 1.25^(1/5) = 1.0456. Step 5: r/100 = 0.0456, therefore r ≈ 4.56% ≈ 4.5% (approximately). The average annual increase is approximately 4.5%.

Question 19

In a district, the population of males increased by 15% and the population of females increased by 20% over a decade. If the male population increased by 3,60,000 and female population increased by 4,80,000, what was the total population of the district a decade ago?

Accepted Answer

Step 1: For males: 15% increase = 3,60,000. Original male population = 3,60,000 ÷ 0.15 = 24,00,000. Step 2: For females: 20% increase = 4,80,000. Original female population = 4,80,000 ÷ 0.20 = 24,00,000. Step 3: Total population a decade ago = 24,00,000 + 24,00,000 = 48,00,000. The total population a decade ago was 48,00,000.

Question 20

A region's population was 8,00,000 five years ago. It increased by 10% in the first two years combined, then by 20% in the next two years, and by 5% in the fifth year. What is the current population?

Accepted Answer

Step 1: Population after first two years = 8,00,000 × 1.10 = 8,80,000. Step 2: Population after next two years = 8,80,000 × 1.20 = 10,56,000. Step 3: Population after fifth year = 10,56,000 × 1.05 = 11,08,800.

Question 21

The population of a city was 5,00,000 in 2015. It increased by 20% in the next 4 years and then decreased by 10% in the following 2 years. What is the population in 2021?

Accepted Answer

Step 1: Population after 4 years (2019) = 5,00,000 × (1 + 20/100) = 5,00,000 × 1.20 = 6,00,000. Step 2: Population after next 2 years (2021) = 6,00,000 × (1 - 10/100) = 6,00,000 × 0.90 = 5,40,000. Therefore, the population in 2021 is 5,40,000.

SSC CHSL Population Problems

SSC CHSL Population Problems — Past Exam Questions

Population Problems— Rules & Concept

Key Points to Remember

Exam-Specific Tips

Population Problems — Practice Questions

60-Second Revision — Population Problems